Re: [PATCH] Re: Problem with setxattr on sockfs with Smack after 971df15bd54ad46e907046ff33750a137b2f0096

From: Casey Schaufler <casey@schaufler-ca.com>
To: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>,
	linux-kernel@vger.kernel.org,
	linux-security-module@vger.kernel.org,
	Stephen Smalley <sds@tycho.nsa.gov>,
	Casey Schaufler <casey@schaufler-ca.com>
Subject: Re: [PATCH] Re: Problem with setxattr on sockfs with Smack after 971df15bd54ad46e907046ff33750a137b2f0096
Date: Wed, 2 Nov 2016 13:09:01 -0700	[thread overview]
Message-ID: <57e9db81-d785-98ab-dd52-47c1f82c76c3@schaufler-ca.com> (raw)
In-Reply-To: <1478115261-29669-1-git-send-email-agruenba@redhat.com>

On 11/2/2016 12:34 PM, Andreas Gruenbacher wrote:
> Casey,
>
> does this patch help?

My tests pass with this patch applied.

>
> (The way how security xattrs are handled by LSM is pretty ugly.

I'm open to suggestions.

>   I'm not
> convinced that it doesn't break something else, yet.)
>
> Thanks,
> Andreas
> ---
>  fs/xattr.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/fs/xattr.c b/fs/xattr.c
> index 3368659..bf09836 100644
> --- a/fs/xattr.c
> +++ b/fs/xattr.c
> @@ -183,11 +183,13 @@ int __vfs_setxattr_noperm(struct dentry *dentry, const char *name,
>  			security_inode_post_setxattr(dentry, name, value,
>  						     size, flags);
>  		}
> -	} else if (issec) {
> -		const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
> -
> +	} else {
>  		if (unlikely(is_bad_inode(inode)))
>  			return -EIO;
> +	}
> +	if (issec && error == -EOPNOTSUPP) {
> +		const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
> +
>  		error = security_inode_setsecurity(inode, suffix, value,
>  						   size, flags);
>  		if (!error)